Light beam scanning device

Abstract

The light beam scanning device ( 1 ) comprises light source device ( 2 ) which emits a light beam, disk-shaped refracting optical element ( 3 ) which refracts a light beam emitted from light source device ( 2 ), and drive motor ( 4 ) which rotationally drives refracting optical element ( 3 ). In light beam scanning device ( 1 ), when the light beam emitted from light source device ( 2 ) is made incident on refracting optical element ( 3 ) while having refracting optical element ( 3 ) rotated, and the light beam is refracted with refracting optical element ( 3 ) and scanned in a predetermined direction. Such light beam scanning device ( 1 ) can be downsized even when a light beam scanning is carried out at high resolution. Moreover, light beam scanning device ( 1 ) has superior temperature characteristics and can scan a light beam of stable strength.

1 - 19 . (canceled) 
   
   
       20 . A light beam scanning device in which a light beam is scanned in a predetermined direction comprising:
 a refracting optical element in which the refraction direction varies depending on the position of the circumferential direction;   a light source device which emits a light beam toward said refracting optical element; and   a rotationally driving mechanism which rotates said refracting optical element to move in the circumferential direction the position of incidence of a light beam on said refracting optical element.   
   
   
       21 . The light beam scanning device as set forth in  claim 20  wherein said refracting optical element allows an incident light beam from said light source device to pass through from one end face and emit from the other end face. 
   
   
       22 . The light beam scanning device as set forth in  claim 21  wherein said light source device comprises a light-emitting element that emits a light beam, and a lens that changes the divergence angle of a light beam emitted from said light-emitting element; at the same time, it emits a light beam in the direction roughly perpendicular to the rotational plane of said refracting optical element. 
   
   
       23 . The light beam scanning device as set forth in  claim 21  wherein said light source device comprises a light-emitting element that emits a light beam, and a collimator lens that converts a light beam emitted from said light-emitting element to a parallel beam; at the same time, said light source device adopts a configuration in which a light beam is emitted in the direction parallel to the rotational plane of said refracting optical element or in the slanting direction; wherein, with respect to said light beam emitted from said light source device, arranged is a mirror which reflects said light beam in the direction roughly perpendicular to the rotational plane of said refracting optical element and makes said light beam incident on said refracting optical element. 
   
   
       24 . The light beam scanning device as set forth in  claim 21  wherein said refracting optical element comprises multiple division regions divided in the circumferential direction, and adopts a configuration in which an inclined face that refracts an incident light beam in a predetermined direction is formed on each division region. 
   
   
       25 . The light beam scanning device as set forth in  claim 24  wherein, in each of said multiple division regions, said inclined face has a certain angle of inclination; in said multiple division regions aligned in the circumferential direction, the angle of inclination of said inclined face be changed continuously. 
   
   
       26 . The light beam scanning device as set forth in  claim 24  wherein said division regions are divided at approximately equiangular intervals. 
   
   
       27 . The light beam scanning device as set forth in  claim 26  wherein a light beam can be made incident on the central position in the circumferential direction of said division region by emitting a light beam at regular intervals from a light source device. 
   
   
       28 . The light beam scanning device as set forth in  claim 24  wherein said inclined face be formed only on one side of said refracting optical element wherein the inclined face be configured in such a way that the angle of inclination θw of said inclined face with respect to the rotational plane of said refracting optical element, the scanning angle θs of a light beam emitted from said refracting optical element, and the refractive index n of said refracting optical element satisfy the relationship of
   sin(θ w+θs )= n ·sin θ w      
   
   
       29 . The light beam scanning device as set forth in  claim 21  wherein an inclined face continuous in the circumferential direction be formed in said refracting optical element, and the angle of inclination of said inclined face changes continuously in the circumferential direction. 
   
   
       30 . The light beam scanning device as set forth in  claim 29  wherein said inclined face is formed on only one side of said refracting optical element, wherein said inclined face be configured in such a way that the angle of inclination θw of said inclined face with respect to the rotational plane of said refracting optical element, the scanning angle θs of a light beam emitted from said refracting optical element, and the refractive index n of said refracting optical element satisfy the relationship of
   sin(θ w+θs )= n ·sin θ w      
   
   
       31 . The light beam scanning device as set forth in  claim 21  wherein a refraction preventive treatment be done at least at the end face on the light beam incident side of said refracting optical element. 
   
   
       32 . The light beam scanning device as set forth in  claim 21  wherein said refracting optical element can be formed with a resin. 
   
   
       33 . The light beam scanning device as set forth in  claim 21  wherein said refracting optical element is formed with glass. 
   
   
       34 . The light beam scanning device as set forth in  claim 24  wherein said inclined face is configured in the circumferential direction. 
   
   
       35 . The light beam scanning device as set forth in  claim 24  wherein said inclined face is configured in the radial direction. 
   
   
       36 . The light beam scanning device as set forth in  claim 20  wherein said device be equipped with a means for position detection which detects the rotational position of said refracting optical element and, based on the detection result of said position detection means, the rotation of said refracting optical element by said rotationally driving mechanism and an emission of a light beam from said light source device be controlled. 
   
   
       37 . The light beam scanning device as set forth in  claim 26  wherein said rotationally driving mechanism rotate said refracting optical element at a constant rate, and said light source device emit a pulse-shaped light beam at regular intervals toward said refracting optical element. 
   
   
       38 . The light beam scanning device as set forth in  claim 29  wherein said rotationally driving mechanism is allowed to rotate said refracting optical element at a constant rate, and said light source device emits a light beam continuously toward said refracting optical element. 
   
   
       39 . The light beam scanning device as set forth in  claim 29  wherein said inclined face is configured in the circumferential direction. 
   
   
       40 . The light beam scanning device as set forth in  claim 29  wherein said inclined face is configured in the radial direction. 
   
   
       41 . The light beam scanning device as set forth in  claim 29  said rotationally driving mechanism rotate said refracting optical element at a constant rate, and said light source device emit a pulse-shaped light beam at regular intervals toward said refracting optical element.